Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
In Questa, $60\%$ of adults go to work by car.
(a)[3]
A random sample of $12$ adults is chosen from Questa. Find the probability that fewer than $10$ travel to work by car.
(b)[5]
A random sample of $150$ adults is taken from Questa. Use an approximation to find the probability that fewer than $81$ travel to work by car.
(c)[1]
Justify the use of the approximation in part (b).
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct complementary probability setup using binomial distribution” …